Antenna



FIG. 1 is a top plan view of an antenna on a base in broken lines;

FIG. 2 is a side elevation view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top plan view of the antenna without a base; and,

FIG. 5 is a side elevation view thereof.

The broken line showing of a base represents environment only and forms no part of the claimed design. 

CLAIM The ornamental design for an antenna, as shown and described. 